Stuffing box



`Fan. 5, 1943. H. ALLEN 2,307,346

sTUffFING Box Filed Jan. 27, 1941 MINI!!! INVENTOR Patented Jan. 5, 1943s'rUFFiNG Box Herbert Allen, Houston, Tex., assignor to Cameron IronWorks, Houston, Tex., a corporation of Texas Application January 27,1941, Serial No. 376,128 2 claims. (ci. 2st-.ssi

This invention relates in general to apparatus for packing jointswherein plastic packing material is employed and has for its generalobject the provision of a means for limiting the pressure in packingsystems employing plastic packing material.

It has been found in practice that when a workman operates the threadedram of a packing system employing plastic packing material to injectmore packing material into the system to increase the pressure on thematerial in said system, there is a tendency for the Workman to take uptoo much on the ram, thereby placing too great a pressure on the packingmaterial. This results not only in diiiicult operation of the movableparts with which the packing forms a seal, but also results in excessivewear of said parts.

A more specific object of this invention is to provide means in apacking system employing plastic packing material to prevent theapplication of too great a pressure on the packing material containedtherein.

Another object of this invention is to provide in a system containing aiiuid or plastic substance, a ram which is incapable of exerting morethan a predetermined maximum pressure.

A further object of this invention is to provide an adjustable means forlimiting the amount of pressure which may be applied to the packing in aplastic packing system. l v

Still further objects will appear in the following description taken inconnection with the appended drawing which illustrates an embodiment ofthe present invention.

In the drawing:

Fig. 1 is a horizontal sectional View of oil or gas Well equipmentprovided with plastic packing systems embodying the present invention.

Fig. 2 is a longitudinal sectional View of a ram or rplunger having apressure relief valve embodied therein.

In Fig. 1 of the drawing, there is shown a structure in which thepresent invention is embodied. As illustrated, the tting I is adapted tobe connected to an oil or gas well so that ow from the well will takeplace through the tting and choke 2 and thence through the part 3 of thefitting into the flow line (not shown) which is coupled to said part 3.The tting I' is integral with the part 3, the connection being indicatedby reference character 4. Bifurcated rings 5 are adapted to' resilientlyreceive and support the choke 2 while it is being clamped into positionbetween the screw threaded members 6 and 1. Member 6 is adapted to betightly screwed into position within bore la in the tting I whereas thescrew threaded member 1 is constructed and mounted within the part 3 foraxial adjustment therein. The end faces of the members 6 and 1 arerecessed to receive the ends of the choke 2', and in mounting the choke2 in position, one end of the choke is placed into position in therecess of the member 6. The screw threaded member 1 is then rotated tocause the same to be axially displaced to engage the other end of thechoke and clamp the same in position between the two members 6 and 1.

The bore Ia extends through the main portion of the fitting I in axialalignment with the aperture in the choke 2 and a valve member I2 isaxially displaceably mounted Within said bore. Said valve is adapted tobe moved into seating engagement with the end of the member 6 to closeoif the ow of uid from the well through the tting I into the choke 2. Aportion of the bore which receives the valve body I2 is enlarged andthreaded to receive a bushing I0 which in turn has a portion providedwith internal threads adapted to cooperate with the threadsl on a valve`stem II which is connected with the valve body I2 and serves todisplace said valve body to open and closed positions.

In order to prevent leakage about the adjustable clamping element 1, anannular recess I3 is provided within the part 3 about said element 1.Said recess communicates with a threaded port into which a tting I4 ismounted. Said tting I4 is in the form of a cylinder having a threadedbore therein adapted to receive a threaded ram or plunger I5 providedwith a. head I6 by means of which said ram may be rotated to cause thesame to enter the fitting I4 and displace plastic packing material 8contained therein into the annular recess I3 in order to seal the jointbetween the part 3 and the screw threaded member 1 against leakage. Thelower end of the cylindrical itting I4 is provided with a ball checkvalve I1 to prevent escape of the packing material therefrom uponremoval of the ram I5.

The portion of tting I which contains the bushing I0 and also thebushing I0 itself are provided with communicating annular recessesadapted to receive plastic packing material 8 to seal the bushing I0within the fitting I and to seal the valve stem II within the bushingI0. The portion of iitting I surrounding the bushing I0 is provided witha threaded port for receiving a cylindrical iitting Il identical to thatshown mounted in the part l.

As pointed out hereinbefore, there is a tendency on the part of workmenin tightening the rams or plungers corresponding to the plunger I shownin the drawing in order to put pressure on the packing to tighten themtoo much, thereby applying greater pressure to the plastic packingmaterial than is necessary. As above stated, this causes excessive wearand diillcultV operation. In order to avoid overtightening of the ramI5, the latter, in accordance with the present invention, is providedwith a spring loaded valve adapted to open when the pressure applied tothe plastic packing material exceeds a predetermined value.

In Figure 2 of the drawing, one construction of the ram I5 is shownwhich will operate to avoid the above pointedout disadvantages. Asshown, the ram I5 is provided with a bore I8 extending axiallytherethrough. Bore I8 is constricted midway between the ends of the ramI5 to form a valve seat I9. The portion of the bore I8v between thevalve seat and the head of said ram is provided with ducts or ports 20,which place said bore in communication with the exterior of the ram I5.A valve body 2l shown in the form of a ball is mounted in the bore I8and is adapted to be seated upon the seat I9. A helical coil spring 22is positioned in the bore I8 and has one end engaging the ball valve 2lto urge the latter upon the seat I9. The head end of the bore I8 isthreaded to receive a screw 23 which engages the other end' of thespring 22 and is adjustable toi'vary the degree of compression of thespring 22 and the force applied by said spring urging the valve 2i on toits seat I9.

With this construction, when the ram I5 is rotated to cause the same toenter the cylindrical tting I4, the plastic packing material will bedisplaced from the cylinder Il into the joint to be sealed until thepressure exerted upon said plastic packing exceeds the force exerted bythe spring 22 on the ball valve holding the latter upon its seat. Whensaid pressure is exceeded, the valve 2i will be moved from its seat, andany further displacement of the ram into the cylinder Il will merelycause the plastic packing material to flow through the bore I8 outthrough the ports or ducts 20. Thus, excessive pressure of the plasticpacking material within the packing system will be avoided.

From the foregoing description. it will be realized that the presentinvention solves a practical problem standing in the way of the fullexploitation of plastic packing systems and removes the human elementheretofore involved in the degree of pressure placed upon plasticpacking and the difficulties resulting therefrom.

Having described my invention. I claim:

l. A stuillng box for plastic packing comprising a housing having a boreextending therethrough. the wall of said bore having a circumferentiallyextending recess therein, said housing having a socket thereincommunicating with said bore. a cylinder having an axial bore formedtherein and having one end mounted in said socket. the axial bore insaid cylinder at the end mounted in said socket having a valve seatformed therein, a valve positioned on said seat. a pressure applying ramoperatively mounted in the bore of said cylinder, said pressure applyingram comprising a body having a pressure applying end face and a head,said body having a bore extending axially therethrough and a cross ductextending transversely therethrough adjacent the head, said bore havinga constriction between the cross duct and the pressure applying end:face to form a valve seat, a valve in the head end of said bore, aspring having one end engaging said last-recited valve, and a screwthreadedly adjustably mounted in the head end of said bore and engagingthe other end of said spring to vary the force exerted by said spring onthe last-recited valve urging the latter on its seat.

2. A stuiing box for plastic packing comprising a housing having a boreextending therethrough, the wall of said bore having a circumferentiallyextending recess therein, said housing having a socket thereincommunicating with said bore, a cylinder having an axial bore formedtherein and having one end mounted in said socket, the axial bore insaid cylinder at the end mounted in said socket having a valve seatformed therein, a valve positioned on said seat. a pressure applying ramoperatively mounted in the bore of said cylinder, and yieldable means incontact with the plastic packing at the region of application ofpressure thereto by the ram for yielding under a predetermined maximumpressure on said plastic packing.

HERBERT ALLEN.

